1. Field of Art
The present invention relates to a coding device for automatic conveyor routing and address systems, particularly of the power and free type; including a stationary selector and a plurality of code readers disposed at selected intervals along the conveyor for reading the selected address.
2. Description of Prior Art
Magnetic coding devices for routing systems have not always been effectively implemented to provide efficient and reliable means for routing various moving loads to specified addresses. The commonly used system for magnetic coding and reading is illustrated by U.S. Pat. Nos. 2,857,059, 3,406,639, 3,168,268, 3,735,300, 3,100,040 and 3,173,533. Patents -040, -300, -268 and -639 illustrate the most common design. A series of magnets are disposed along a moving carrier. The magnets, utilizing their various N-S configurations, are read on a lead signal at every read station. Normally these read stations comprise a plurality of reed switches in the proper permutations or associated reed switches are disposed at every station and selectively filtered. If the signal from the magnetic alignment is in the proper permutation then an operation is performed as shown in Patent -533.
In addition, the magnets have to be set manually, thus requiring the conveyor or carrier to stop in order to bias the magnets to the proper address condition (-268, -040, or -300). Because of the reliance on reed switch interpreting circuits the code readers are fixedly set to read the proper address as in Patent -300. Thus to have the code reader read a different address condition, manual changes need be performed to realign the reading elements to the proper address configuration. If this realignment is of sensitive reed switches, damage could easily occur to the device from the constant realignment. For instance, in -533, realignment of the read station would necessitate signal pickup coil 80 (FIG. 2) being transferred and secured in a different position. Since magnetic patches 14 do not carry strong magnetic flux, any realignment must be exactly located such that unwanted cross-electrical interferences or errors by the conveyor selecting mechanism are avoided.
Patents -533 and -059 illustrate the additional problem of demagnetizing substances which can produce errors in the address selecting mechanisms. The demagnetizing substances could consist of any appropriate substance afloat in the air. Often demagnetizing substances could consist of metallic beams or conduits which pick up small elements of magnetism resulting in conveyor system errors.
In addition, these magnet carrying conveyors are susceptible to outside environmental pressures common to a conveyor system. Most often these environmental pressures are collisions between carriers which can severely vibrate a load and encoded mechanism. The encoded mechanism may lose its address or is read as an incorrect address. Since severe collisions occur in a power and free system, elaborate and costly stop mechanisms must be employed or a different system of encoding the carrier's memory must be utilized.